Drafting instrument.



} E. Z. LESH.

DEAFTING INSTRUMENT.

APPLICATION FILED SEPT. 17. 1912.

1 127 33 Patented Feb.2, 1915.

mnesses inventor zen of the United States, residing yertices of the angles 7' and 7:, thus determinmg the axis of rotation of triangles M and EDWIN Z. LESH, OF HARTFORD, CONNECTICUT.

DRAF'I'ING INSTRUMENT.

Specification of Letters Patent.

Patented Feb. 2, 1915.-

Application fled September 17, 1912. Serial No. 720,792.

To all wlmm it may concern:

Be it known that I, EDWIN Z. Lesa, a citiat Hartford, in the county of Hartford and State of Connecticut, have invented a new and useful Drafting Instrument, of which the following is a specification. a

My invention relates to a combination in one convenient instrument of the essential elements of the 9060-30 triangle, the 904545 triangle and the protractor, three instruments commonly used in drafting, the object of which is a labor and time saving device. This object is attained by the mechanism .illustrated in the accompanying drawing in which M and N are two triangular parts shaped from any suitable material as wood, amber,

sheet metal, etc.; the homologous edges a and b, c and d, e and f of the triangles M and N respectively are equal; the homologous angles 9 and h are each; the homologous angles j and k are 45 each; the

triangle N has a projecting member- Q, cir

cular in shape, at the center of which a threaded stud, P rigidly fixed to form a pivot for the triangle M, a corresponding portion of the triangle M bein cut away to fit the projection Q, substantia ly as shown;

the stud P is located at a convenient point in the lines e andjf, and equidistant from the N; the triangle N is provided with a protractor scale arranged concentric with the stud. pivot, or axis P; to the triangle Mis rigidly fixed a plate L, of celluloid or other suitable material, of irre lar shape, designed to engage the pivot and provide a having equal legs; an

pro ecting member R, rovided with a ver- 'mer scale adapted to indicate on the said gotractor scale the degree of inclination tween the edges (1 and b, when one member (M) has been revolved about P upon the other member (N) substantially, as shown;

' P is a thumb-nut, which engages the threaded stud P, and firmly fixes the two members M and N in any relative adjustment by binding the Plate L against Q,t he circular projection o the trian le N. By this construction the members lie in the same plane.

The dash-and-dot lines represent the relative position of the triangles :M and N when the edges e and f are brought into coinciand N are made to' dence by revolving one member upon the other. In this position the edge 0 forms an angle of 90 with the edge 6; the edge 0 45 being the acute angles of a right-triangle the index reading of the protractor scale .is 90 being the sum of the two 45 angles j and It included between the ed es (1 and b. .Thus in one of its possible. adjustments and by virtue of the inclinationof the edges of its members with re-. .spect to each other, the instrument contains at once a 90, two 60, two 45, and two 30 angles, being all the essential elements of triangles, said members being adjustably combmed in such construction as to constitute a protractor substantially as herein set forth. I I

Since either of the edges (1 or b may be applied to the straight edge, T'square, or other wise used as a base from which to protect any desired angle, the device is evidently very handy and convenient as'a protractor.

The herein described device may be applied wherever either of the above mentionedtriangles or a vprotractor can be used, thus constituting in a practical sense a time and labor saving drafting instrument of universal application.

I claim: a v 'In a drafting instrument two members of suitable materlal (as celluloid), and rightangle' triangular in shape, having their homologous edges and angles equal respectively, one acute angle of each member being 30, the other 45; one member being provided with a protractor scale, the other member having rigidly secured thereto a plate provided with a vernier scale adapted to indicate on said protractor scale the degree of inclination between certain homolo ous edges of said members; the said,mem rs being pivotally articulated in such manneras to combine in triangular construction a 90, two 60, two 45, and two 30 angles at one 'ble setting of the said adjustable mem rs.

. EDWINZ. LESH. Witn:

. Beam Pass-mam,

PAUL J. Zremrzxr. 

